Three standout costumes from the insect world include lacewing larvae known as “junk bugs” (left), bagworm moth caterpillars (middle), and case-building caddisfly larvae. (Photos by [left to right] Judy Gallagher, Flickr, CC BY 2.0; Biswas.rishov, Wikimedia Commons, CC BY-SA 4.0; and Bob Henricks, Flickr, CC BY-SA 2.0)

Adrienne Antonsen

By Adrienne Antonsen

Halloween is upon us, and for many people that means transforming themselves into fantastic creatures or characters. Feeling stuck deciding on a costume? Take inspiration from these insects that are masters of disguise!

Junk Bugs

This lacewing larva (Neuroptera: Chrysopidae), one of a group colloquially known as “junk bugs,” incorporated ant exoskeletons into its debris pile (Photo by Judy Gallagher, Flickr, CC BY 2.0).

Lacewing larvae (Neuroptera: Chrysopidae) are colloquially known as “junk bugs” due to their propensity for piling rubbish upon their backs. Environmental debris like lichen, moss, and dirt are popular choices, but junk bugs will sometimes even add the carcasses of their prey to the load. These junk piles disguise the lacewing larvae, camouflaging them both visually and chemically from potential predators including cannibalistic con-specifics.

If detected, the debris can form a protective barrier against attack. In a study between Mallada desjardinsi lacewings and multicolored Asian lady beetles (Harmonia axyridis), lacewing larvae with junk piles experienced far lower detection and capture rates than larvae whose piles had been removed.

Better to trick than be a treat!

Case-Building Caddisfly Larvae

Caddisfly larvae can build exceptionally beautiful cases when stones of varying colors are used, as seen with this Neophylax consimilis. (Photo credit: Bob Henricks, Flickr, CC BY-SA 2.0).

If dressing up in trash doesn’t sound very appealing, how about gems? Caddisfly larvae (Trichoptera) are famous for their self-ornamentation. Aquatic as nymphs, caddisflies build cases around themselves using silk and materials gathered along the riverbed. Materials can include sand, stones, shells, and plants.

At the individual level, these cases can protect the insects from aquatic predators. At the community level, caddisfly larvae have the potential to serve as bioengineers that exert significant effects on streambed geomorphology.

Bagworm Moth Caterpillars

Some bagworm moth larvae (Lepidoptera: Psychidae) are known as log cabin caterpillars; during larval development, they rebuild their wooden homes multiple times as they grow progressively larger (Photo by Biswas.rishov, Wikimedia Commons, CC BY-SA 4.0).

Some of the most impressive costume creators of the bug world have to be bagworm moth larvae (Lepidoptera: Psychidae). These insects construct entire wooden houses to wear!

During the entirety of their larval development period, bagworm moth caterpillars reside within protective cases they build around themselves out of precisely placed twigs and thorns. (Some even resemble tiny log cabins!) These cases have made the study of bagworm moth larval growth rates difficult, as the caterpillars never fully emerge from the housing. While studying the relationship between case size and caterpillar size in Eumeta crameri bagworm moths, researchers discovered that the length of the largest stick in a case directly corresponded to the larva’s developmental stage. Larval surface area roughly doubles at each instar, requiring bagworm moth caterpillars to expand their housing as they grow.

Woolly and Waxy Nymphs

Insects like woolly alder aphids (Prociphilus tessellatus) decorate themselves in white, waxy secretions that give them a cloud-like appearance. (Photo by Judy Gallagher, Flickr, CC BY 2.0)

Insects like flatid plant-hoppers (Hemiptera: Flatidae) decorate themselves in white, waxy secretions that give them a cloud-like appearance. (Photo by Guido Bohne, Flickr, CC BY-SA 2.0)

Some insects, instead of collecting materials to construct a costume with, use substances produced from their own bodies. Immature stages of woolly aphids (Hemiptera: Eriosomatinae), flatid plant-hoppers (Hemiptera: Flatidae), and other insects adorn themselves in angelic wisps of white wax secretions. Such waxy coatings can shield insects against predators, protect against ultraviolet rays, and help retain moisture. A plethora of insect species don this waxy apparel, potentially utilizing a common signal to deter predators that have learned to associate white filaments with distaste.

The insect wax secretions also show similarities to the white pubescence of young plant tissues. Insects may mimic the pubescence to camouflage themselves against plants, while plants may mimic insect wax to give the appearance of a crowded feeding site. Altogether, the widespread use of white waxy coatings by both plants and insects may indicate a mimicry complex.

Wax isn’t the only material a bug can produce for costume creation, though. Our next insect makes its entire outfit out of bubbles!

Spittlebugs

This meadow spittlebug (Philaenus spumarius) nymph is taking a peek outside of its protective fortress of bubbles (Photo by Elke Freese, Wikimedia Commons, CC BY-SA 2.5).

Why live inside a bubble when you can live inside a bunch of bubbles? Spittlebugs (Hemiptera: Cercopoidea) do just this, creating a protective layer of biofoam out of liquid-coated air bubbles released from their spiracles. These bubbles are believed to serve as both predator defense and a temperature- and moisture-controlling microclimate. Researchers recently looked into the biofoam further to determine how it may serve as a light attenuator. They found that nymphs of the rice spittle bug Callitettix versicolor experienced lower survival and slower developmental rates under higher intensities of light, but they were able to adjust the size of their bubbles in response to changing light intensity—smaller bubbles helped block higher intensities of light.

Whether you plan to dress up for Halloween this weekend or are brainstorming ideas for next year, these costumed insects are bound to spark your creativity!

Adrienne Antonsen is a survey field leader for the Coconut Rhinoceros Beetle Response team in Hawai’i. Email: adrienne.k.antonsen@gmail.com.